Deadly Disease Hits New York Horses
In late October, the USDA confirmed two Suffolk County horses tested positive for the West Nile virus. Of 22 symptomatic horses, another 10 have been confirmed to have West Nile antibodies. A Rockland County horse was also being tested. Cases began appearing in August and were initially misdiagnosed as EPM. Thirteen of the 22 horses have died or been euthanized.
The West Nile virus surfaced in people in New York City in August. Originally misdiagnosed as St. Louis encephalitis, the identification of West Nile was ultimately made thanks to a Bronx Zoo veterinarian who noted an unusually large number of dead crows and reported it (see November 1999 issue).
West Nile virus has been detected in mosquitoes and birds in New Jersey, Connecticut and Maryland. It has not been found outside these states, as of late October.
Horses are extremely susceptible to this virus, mortality rate is over 40% compared to around 10% or less for humans. It is spread by mosquitoes and possibly by other blood-sucking insects. The major source, as with the other types of encephalitis, is wild birds.
Although the USDA is not currently quarantining horses with West Nile, there is some evidence that horses with sufficient levels of virus in their blood may infect some mosquitoes and therefore other horses as well. Direct horse-to-horse or horse-to-human transmission does not occur through routine contact or contact with body secretions.
While no restrictions are in force here yet, Hong Kong banned the import of U.S. horses and poultry products as a result of the virus and the European Commissioner for Health and Consumer Protection announced restrictions on horses imported from New York, New Jersey and Connecticut until Jan. 31, as a precautionary measure.
The USDA will investigate any case of neurological disease in a horse in any state if it meets the criteria of anorexia, depression or listlessness, plus any three of these signs: fever, weakness of hind limbs, flaccid paralysis of the lower lip, impaired vision, ataxia, head pressing, aimless wandering, convulsions, inability to swallow, circling, hyperexcitability, paresis, coma, or death.
The threat to Northeast horses should end for this year with the first hard frost. However, the disease could emerge next year if the virus successfully winters in dormant mosquitoes, nonmigratory birds or other hosts. Southern states may still be at risk this year, if the virus is introduced by birds migrating south. These same birds could also carry the virus back north next year, when problems could be expected to peak around the same time — late summer and early fall.
As of yet, no vaccine has been developed, but suggestions are flying. Horses do not become lifelong carriers and true non-symptomatic carriers have not been identified. Intensive nursing and supportive care can save just over 50% of the infected horses. Convalescence after recovery is prolonged.
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Click here to view ”Preventative Measures.”
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USDA Ends Illinois Study
USDA veterinarian Gifford S. Jacobsen reports the case is closed on the mysterious illness in Illinois Horses (see October 1999). All blood samples for antibodies to known viral illnesses were negative. Although high environmental temperatures are suspected as playing a role in the Illinois problem, the fact these horses had changes in their blood counts suggesting viral disease and that all cases were confined to a single barn on the premises does suggest a virus was at work. The exact cause remains undiagnosed.
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EIA Outbreak In Pennsylvania
he Pennsylvania Department of Agriculture has confirmed that 21 horses in the northeast corner of the state have tested positive for equine infectious anemia (EIA). Dr. Bruce Schmucker said that two horses sold through an auction in Harford, Pa., on Sept. 18 arrived without Coggins tests, were tested on the site and later turned up positive.
Of the 21 test-positive horses, 18 have been destroyed; the others were quarantined. The two horses at the auction came from Wayne County camp herds, and all the test-positive horses also came from those herds. A third of the 29 horses in one group turned up positive, while a smaller proportion of the second, much larger herd was positive.
No horses that they joined later have tested positive, although horses on 47 Pennsylvania farms have been quarantined. The remaining camp horses are negative and are under quarantine.
Schmucker said it’s unlikely the disease was transmitted to other horses during the auction since the weather that day was chilly and the activity of biting flies was low. The PDA has informed authorities in New York, Maryland and Ohio of exposed equines that moved to those states.
Pennsylvania doesn’t require a negative Coggins test when a horse is sold or transported within the state, unlike the laws in many other states. It does require a negative Coggins test for horses entering the state.
Also With This Article
Click here to view ”Vaccine Use And Health Testing Low Nationally.”
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Back-To-Back Three-Days
Two major three-day events will be held on succeeding weekends next spring, the Rolex Kentucky CCI**** in Lexington, Ky., April 27-30, and the MBNA Foxhall Cup CCI*** in Atlanta, Ga., May 4-7. Foxhall has $200,000 in prize money. The Rolex event, also presented by Bayer, has $135,000 pledged so far.
The Foxhall Farm site is new for eventing, although several 1996 Olympic teams trained there. Much of the cross-country course will be visible from one site and will cross the dressage and show-jumping arena, which seats 3,500. The event is aiming for 35,000 spectators.
Jim Wolf of the USET said that riders “will take their four-star horses to Kentucky and their three-star horses to Georgia. . . . We’re trying to put together a circuit to attract more international competitors.”
For information on the Rolex event, call 606/233-2362; for the Foxhall Cup, call 404/572-7220.
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Futurity Winners Advance To Top Prizes
Two horses that won International Jumper Futurity regional awards in 1995 took the top prizes in major grand prix events this fall. Iron Spring Farm’s Judgement won the $60,000 American Gold Cup at Devon, Pa., and El Dorado 29’s South Shore won the $50,000 The Oaks International in San Juan Capistrano, Calif.
South Shore, ridden by Richard Spooner, has won two other events this year. He is a Holsteiner by Joan Irvine Smith’s South Pacific out of Emerald Isle. Judgement, ridden by Michael Matz, won the IJF Eastern Finals as well as the regionals. He is a Dutch Warmblood stallion, by Iron Springs’ Consul out of Faletta.
The IJF promotes the breeding of sport horses in the United States who will be competitive with their European counterparts.
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N.Y. Helmet Law
Children in New York under age 14 will be required to wear helmets while horseback riding at commercial stables under a law that will take effect Jan. 5, 2000. It mirrors a state law for young bike riders and in-line skaters.
The law will require commercial stables to supply helmets to all young riders and any other customers requesting them. The parents or guardians of kids caught not wearing helmets will also be subject to civil fines of up to $50. The statute does not require helmets for kids riding horses on private property.
The bill was scaled back from an earlier version that called for extensive regulation of commercial riding establishments, including the grading of trails for difficulty.
